Figure 5.

Draper is a multifunctional “Hydra,” participating in all stages of corpse clearance. (1) Draper is required to detect tissue damage (red circles) perhaps via detection of an as-of-yet unidentified ligand released from the wound (blue circles). Hydrogen peroxide emanating from the wound (orange/yellow arrow) bypasses the requirement for Draper ligand binding by directly activating Src42a. Activated Src42a phosphorylates the ITAM domain, which leads to the recruitment of Shark and downstream signaling. This draws the phagocyte toward the debris via cytoskeletal rearrangements. (2) Draper localizes to phagocytic cups during engulfment of cell corpses (red circles) triggering ITAM phosphorylation via Src42a. Shark recruitment and subsequent downstream signaling promotes the cytoskeletal rearrangements required for engulfment. (3) Draper is also required for phagosome maturation and efficient corpse processing via its NPxY motif, which associates with dCED-6/GULP.